中华放射医学与防护杂志
中華放射醫學與防護雜誌
중화방사의학여방호잡지
Chinese Journal of Radiological Medicine and Protection
2012年
4期
379-382
,共4页
吴爱东%张绍虎%张红雁%闫冰%刘磊
吳愛東%張紹虎%張紅雁%閆冰%劉磊
오애동%장소호%장홍안%염빙%류뢰
食管肿瘤%调强放疗%图像引导放疗%摆位误差%剂量学
食管腫瘤%調彊放療%圖像引導放療%襬位誤差%劑量學
식관종류%조강방료%도상인도방료%파위오차%제량학
Esophageal neoplasm%Intensity modulated radiotherapy%Image guided radiotherapy%Setup error%Dosimetry
目的 应用千伏级锥形束CT(kV-CBCT)测量胸段食管癌调强放疗的摆位误差,探讨摆位误差对肿瘤靶体积和周围正常组织受照剂量的影响.方法 21例胸段食管癌患者经图像引导调强放疗,共获得173组CBCT摆位误差数据,利用这些数据在三维治疗计划系统中模拟患者的实际治疗过程,分析摆位误差对肿瘤靶区及周围正常组织受照剂量的影响.结果 21例患者左右、头脚、前后方向的摆位误差分别是(2.73 ±1.85)、(3.19±2.71)和(2.35±1.71)mm.摆位误差对患者GTV的剂量学影响不明显,但误差却使患者95％ PTV( D95％)接受的剂量与标准计划相比降低3.38 Gy,PTV最小剂量(Dmin)和平均剂量(Dmean)分别下降9.83和0.65 Gy,摆位误差的修正提高了计划靶区的适形度和剂量均匀性,标准计划相应值分别为(0.74±0.10)和(1.07±0.02),模拟计划相应值分别为(0.69±0.08)和(1.13±0.07),差异均有统计学意义(t=3.43和-3.91,P＜0.05)；摆位误差对脊髓的最大剂量(Dmax)、双肺和心脏等周围正常组织受照剂量影响,差异无统计学意义(P＞0.05),模拟计划中脊髓的最大剂量均值为(42.20±4.97)Gy,标准计划为(41.37±2.75) Gy,摆位误差使部分患者脊髓最大剂量超过45 Gy,其中1例最大值达到52.8 Gy.结论 kV-CBCT图像引导胸段食管癌调强放疗可减小患者的摆位误差,提高PTV的受照剂量和治疗精度,摆位误差对双肺、脊髓和心脏受照剂量未见明显改变.
目的 應用韆伏級錐形束CT(kV-CBCT)測量胸段食管癌調彊放療的襬位誤差,探討襬位誤差對腫瘤靶體積和週圍正常組織受照劑量的影響.方法 21例胸段食管癌患者經圖像引導調彊放療,共穫得173組CBCT襬位誤差數據,利用這些數據在三維治療計劃繫統中模擬患者的實際治療過程,分析襬位誤差對腫瘤靶區及週圍正常組織受照劑量的影響.結果 21例患者左右、頭腳、前後方嚮的襬位誤差分彆是(2.73 ±1.85)、(3.19±2.71)和(2.35±1.71)mm.襬位誤差對患者GTV的劑量學影響不明顯,但誤差卻使患者95％ PTV( D95％)接受的劑量與標準計劃相比降低3.38 Gy,PTV最小劑量(Dmin)和平均劑量(Dmean)分彆下降9.83和0.65 Gy,襬位誤差的脩正提高瞭計劃靶區的適形度和劑量均勻性,標準計劃相應值分彆為(0.74±0.10)和(1.07±0.02),模擬計劃相應值分彆為(0.69±0.08)和(1.13±0.07),差異均有統計學意義(t=3.43和-3.91,P＜0.05)；襬位誤差對脊髓的最大劑量(Dmax)、雙肺和心髒等週圍正常組織受照劑量影響,差異無統計學意義(P＞0.05),模擬計劃中脊髓的最大劑量均值為(42.20±4.97)Gy,標準計劃為(41.37±2.75) Gy,襬位誤差使部分患者脊髓最大劑量超過45 Gy,其中1例最大值達到52.8 Gy.結論 kV-CBCT圖像引導胸段食管癌調彊放療可減小患者的襬位誤差,提高PTV的受照劑量和治療精度,襬位誤差對雙肺、脊髓和心髒受照劑量未見明顯改變.
목적 응용천복급추형속CT(kV-CBCT)측량흉단식관암조강방료적파위오차,탐토파위오차대종류파체적화주위정상조직수조제량적영향.방법 21례흉단식관암환자경도상인도조강방료,공획득173조CBCT파위오차수거,이용저사수거재삼유치료계화계통중모의환자적실제치료과정,분석파위오차대종류파구급주위정상조직수조제량적영향.결과 21례환자좌우、두각、전후방향적파위오차분별시(2.73 ±1.85)、(3.19±2.71)화(2.35±1.71)mm.파위오차대환자GTV적제량학영향불명현,단오차각사환자95％ PTV( D95％)접수적제량여표준계화상비강저3.38 Gy,PTV최소제량(Dmin)화평균제량(Dmean)분별하강9.83화0.65 Gy,파위오차적수정제고료계화파구적괄형도화제량균균성,표준계화상응치분별위(0.74±0.10)화(1.07±0.02),모의계화상응치분별위(0.69±0.08)화(1.13±0.07),차이균유통계학의의(t=3.43화-3.91,P＜0.05)；파위오차대척수적최대제량(Dmax)、쌍폐화심장등주위정상조직수조제량영향,차이무통계학의의(P＞0.05),모의계화중척수적최대제량균치위(42.20±4.97)Gy,표준계화위(41.37±2.75) Gy,파위오차사부분환자척수최대제량초과45 Gy,기중1례최대치체도52.8 Gy.결론 kV-CBCT도상인도흉단식관암조강방료가감소환자적파위오차,제고PTV적수조제량화치료정도,파위오차대쌍폐、척수화심장수조제량미견명현개변.
Objective To measure the setup errors in thoracic esophageal carcinoma treated with intensity modulated radiotherapy (IMRT) using kilo-voltage cone-beam CT (kV-CBCT),and to evaluate the impact of the setup errors on the dose distributions in tumor target volume and the peripheral normal tissues.Methods Twenty-one patients with thoracic esophageal carcinoma undergoing image guided IMRT (IG-IMRT) were included in this study. Using kV-CBCT,173 setup errors of these patients were acquired before treatment.By shifting the isocenters,these setup errors were simulated in the 3-dimentional treatment planning system and the corresponding impact of the dose distribution in tumor target volume and peripheral organs were evaluated.Results The translational deviations of lateral,longitudinal and vertical directions were ( 2.73 ± 1.85 ),( 3.19 ± 2.71 ),and ( 2.35 ± 1.71 ) mm,respectively.The dose of gross tumor volume (GTV) was not impacted significantly by the setup errors. However,comparing with the standard plan without setup errors,the setup errors in the simulated plan reduced the dose of 95％ planning target volume (PTV) by 3.38 Gy.The dose to PTV Dmin and PTV Dmean were also reduced by 9.83 Gy and 0.65 Gy respectively. The correction of setup errors improved the conformity index (CI) and the homogeneity index (HI) for PTV.The C1 and HI for the standard plan were 0.74 ± 0.10 and 1.07 ±0.02, respectively. The C1 and H1 for the simulated plan were 0.69 ± 0.08 and 1.13 ± 0.07,respectively.Statistically significance was observed in these differences ( t =3.43 and -3.91 respectively,P ＜ 0.05 ). No statistical significance was observed in the dose differences in lungs,spinal cord and heart between the two plans ( P ＞ 0.05).The mean maximum dose of the spinal cord was (42.20 ± 4.97 ) Gy in the simulation plan,which was (41.37 ± 2.75 ) Gy in the standard plan.For some patients,the maximum dose of the spinal cord exceeded the tolerance level of 45 Gy in the simulation plan,and one case even reached 52.8 Gy.Conclusions Using the image guidance of kV-CBCT,the setup errors can be reduced significantly for patients with esophageal carcinoma receiving IG-IMRT.The correction of setup errors can increase the treatment precision and enhance the dose in PTV.No significant dose changes were observed in the lung,spinal cord and heart as a result of setup error correctio.
